Method of making a tubular article



Get. 11, 1938.

J. W. BAXTE R METHOD OF MAKING A TUBULAR ARTIGLE Fi led Dec. 21, 1956 Patented Oct. 11, 1938 I PATENT OFFICE METHOD OF MAKING A TUBULAR ARTICLE James W. Baxter, Ellwood City, Pa., assignmto National Company, a corporation of New I i Jersey Application December 21, 1936, Serial No. 117,083

1 Claim.

This invention relates to a method of making a tubular article and particularly one which is provided with a longitudinal outwardly extending lip or fin in the outer circumference thereof.

An 'object of this invention is to provide an inexpensive method by which a tubular article,

which readily transfers heat between the inner and outer surfaces thereof, can rapidly be made.

The above and further objects will become apparent by referring to the following description and the accompanying drawing, in which:

Figure 1 is an elevation of one embodiment of apparatus for performing the steps of my invention;

Figure 2 is a section online 11-11 of Figure 1; Figure 3 is a section on line III-1110f Figure Figure 4 is a section 'online IV-IV; and Figure 5 is a section on line V-V. Referring more particularly to the accompanying drawing in which apparatus, capable of funcbular blank 2 is appreciably larger,preferably about 10 to 20 percent, than the outside diameter of the tubular blank 4,. so that the adjacent circumferences are of substantially different lengths. Both tubular blanks are preferably made from stainless steel so that they will not corrode but will readily transfer heat.

In commencing to formvthe final productor heat transfer conduit 6 from the t bular blanks 2 and 4, the outer tubular blank 2 j th the tubular blank 4 suitably held therein is passed through a pair of rolls ll. The rollst forming a roll pass 9 are journaled and drivenin any suitable manner (not shown). The roll pass 9 formed by the. rolls 8 is designed to sink the outer tubular blank 2 about the inner tubular blank 4.

5 As the diameter of. the outer tubular blank! is reduced a small portion ill in the circumference thereof is made ,to extend outwardly therefrom. By extending the portion l0 outwardly from the outer tubularblank 2, the length of its circumference is not changed in the rolling operation. The portion II is 'straightand. extends the length of the outer tubular blank 2 while preferably projecting r d ally therefrom. 1

The outer tubular blank 2 is led from the rolls :5 I to a suitably mounted pair of rolls I! which form a roll pass I! in alignment with the rollpass 1 9. The roll pass I3 is designed to further sink the outer tubular blank 2 on the inner tubular blank 4 and also act upon the outer tubular blank 2 to cause the portion Ill thereof to project fairly sharply therefrom I In order to finish the-heat transfer conduit 6, the tubular-blanks 2 and 4 are passed through a pair of rolls l4 which form a final roll pass IS. The rolls H are journaled and driven in any suitable manner (not shown) and the roll pass I6 is aligned with the roll passes 9 and I3. The function of the roll pass I6 is to completely sink the outer tubular blank 2 upon the inner tubular blank 4 and to'form a straight, longitudinally extending drip-lip flange, or fin l8 which is substantially V-shaped in section from the-portion l0 of the outer tubular blank 2. All of the inner'surface of the outer tubular blank 2 except that of the fin l8 is made bear upon, or fit-tightly against, 4

the outer surface of the inner tubular blank 4 so that the .best possible heat transferring relation is secured therebetween.

The heat transfer conduit 6 is particularly adapted for use as a liquid regenerator or cooler where clean operating partstare required. Both the inner and outer surfaces of .the finished ar-' ticle resist corrosion and, due to the round bore of the inner tubular blank 4, both surfaces thereof are easily cleaned.

While I have shown anddescribed one form of apparatus for performing the steps of my method of making a tubular article, it will be appreciated that variations thereof can be made without departing from the scope of my invention as defined by the following claim.

' I claim: I

That method of manufacturing a heat transfer conduit having a smooth inner bore and a longitudinally directed radially outwardly extending ing substantially the same cross-sectional thickness of the outer tubular blank. 

